1. Field of the Invention
The present invention relates to devices and methods for enhancing distance vision, and, more particularly, to such devices and methods for providing an adaptive reticle display in binoculars having both direct and image-processed viewing options.
2. Description of Related Art
Binoculars have long been known in the art for providing increased distance vision with depth perception (FIG. 1). A typical binocular has two sides, each of which 10 has an objective lens 11 that creates an image that passes through a prism 12 for correctly orienting the image. Some binoculars include a reticle 13 that is superimposed on the image to achieve distance estimation. The image downstream of the prism 12 is focused at the reticle 13, and an eyepiece 14 permits the user 15 to focus on the reticle 13.
More complex binoculars are also known that have one side 20 through which a displayed image can be transmitted through the eyepiece 21 (FIG. 2). The direct-image optics are substantially the same, but a visual display 22 and projection optics 23 are positioned upstream of the eyepiece 21 and reticle 24. Here the prism 25 has one surface that is not completely reflective and serves as a beamsplitter 26, permitting the user 27 to see through the prism 25. The characteristics of the beamsplitter 26 determine the mix of the display 22 and scene viewed by the user 27. Exemplary characteristics can include intensity splitting (e.g., 80/20), spectral (e.g., red/visible without red), and polarized (p and s).
Typically a user will not wish the reticle to be superimposed on a displayed image, for example, if the size, orientation, or location of the displayed image is different from that of the scene viewed through the objective and prism.
Therefore, it would be desirable to provide a binocular system that can eliminate visualization of the reticle when viewing a displayed image.